sql - How can I see how many users have a particular association in Rails?

Question

I'm trying to figure out how I can use the Rails console to get the number of users that have two particular associations. Here's my conditions:

A User can have many DropboxUser accounts linked and many DriveUser accounts linked to their account via a foreign key. In my model declaration, both DropboxUser and DriveUser belongs_to :user. In conjunction with the previous statement, a User has_many :dropbox_users and has_many :drive_users. I know I have all of my models linked, so now I want to know how I can find out how many User accounts have both a DropboxUser account and a DriveUser account associated with them.

Here's some of the code I've tried (unsuccessfully):

User.count(:conditions => "dropbox_users.uid='user.id' AND drive_users.uid='user_id'")

Perhaps I was headed in the right direction with my last query, perhaps not. It told me no such column: dropbox_users.uid.

Answer 1

dropbox_usersクエリを実行するに は、参加する必要があります。

User.joins(:dropbox_users).joins(:drive_users).count

また、joinsを使用しているINNER JOINため、Dropbox と Drive の両方のアカウントを持つレコードのみが返されます。